When looking through Revelation, there’s a partial explanation to Matthew 24:22 (shortened the days). In Revelation 8:12 the fourth angel sounded his trumpet and a third part of the sun, moon, and stars were darkened so that their light did not shine for a third part of it. Now, in Revelation 16:8 the angel poured his vial (bowl) upon the sun allowing it to scorch men with great heat. Could this be what Jesus was referring to when he talked of the shortening of the days (not the period of time for the tribulation)?
I don’t believe these verses apply to shortening the length of Earth’s days, but to the decrease in light reaching Earth due to smoke and debris from the Seal and Trumpet judgments clouding the atmosphere. Shortening the length of a day by 1/3 would require a 50% increase in the speed of rotation on our axis. The Earth would fly apart and take everyone with it.
I think Rev. 16:8 describes the sun going super nova prior to going dark as Matt. 24:29 indicates. In the millennium, the New Jerusalem will be Earth’s source of light (Rev. 21:23-24).